Gas turbine engines are generally known and, when used on an aircraft, typically include a fan delivering air into a bypass duct and into a compressor section. Air from the compressor section is passed downstream into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
Turbine rotors drive compressor and fan rotors. Historically, the fan rotor was driven at the same speed as a turbine rotor. More recently, it has been proposed to include a gear reduction between the fan rotor and a fan drive turbine. With this change, the diameter of the fan has increased dramatically and a bypass ratio, or volume of air delivered into the bypass duct compared to a volume delivered into the compressor has increased. With this increase in bypass ratio, it becomes more important to efficiently utilize the air that is delivered into the compressor.
One way to increase the efficiency of the use of this air is to increase the pressure at the exit of a high pressure compressor. This elevated pressure results in a high temperature increase at the exit of the high pressure compressor. The elevated temperature at the exit of the high pressure compressor is known in the art as T3.
In order to cool the high pressure compressor, as well as other turbine engine components with elevated temperatures, existing designs direct cool air from other portions of the engine, such as a bypass flowpath, onto the components that are desired to be cooled. In some instances the air being utilized in this manner is too cool relative to the temperature of the component, and the air will not provide proper cooling unless it is conditioned to be the correct temperature.